[Gllug] [Somewhat OT] POSIX regex in C
adrian at mcmen.demon.co.uk
Wed Jul 13 11:49:00 UTC 2011
On Wed, July 13, 2011 12:01 pm, Nix wrote:
> On 9 Jul 2011, Adrian McMenamin stated:
> You want a #define up here (_XOPEN_SOURCE, _GNU_SOURCE or something) to
> specify what language standard you're conforming to. The default is
> 'just ISO C', which is unlikely to be what you want.
>> #include <regex.h>
>> struct blocklist* getnextblock(void** lastblock, void** head, char* buf)
>> printf("LINE:%s", buf);
>> regex_t reg;
>> regmatch_t addresses;
>> char pattern = "^([0-9a-f]+)-([0-9a-f]+)";
>> int xreg = regcomp(®, pattern, REG_EXTENDED|REG_NOSUB);
>> printf("Regcomp returns %d\n", xreg);
>> int match = regexec(®, buf, (size_t)3, addresses, 0);
> POSIX states:
>> If _nmatch_ is 0 or REG_NOSUB was set in the cflags argument to regâ
>> comp(), then regexec() shall ignore the _pmatch_ argument.
> (nmatch == arg 3, pmatch == arg 4).
> So two of your arguments are useless
You are right of course - though I had just stuck that REG_NOSUB in when I
was trying to debug it/eliminate that as the issue.
> reg*() are in POSIX (and have been for fifteen years or more), and are
> very widely used, so you can trust that they work. Something else is
> wrong, but your example does not give us enough information to be sure
> what it is.
As it turned out the real issue was a leak elsewhere.
> NULL && (void)
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